The wild-type yeast strain Zygosaccharomyces bisporus CBS 702 produced alph
a-hydroxyketones (acyloins) from amino acid precursors after transamination
to the corresponding 2-oxo acids. The key enzyme of the subsequent decarbo
xylation and C-C bond forming reaction, pyruvate decarboxylase (PDC), was e
xamined for its substrate- and stereo-specificity. A wide variety of satura
ted and unsaturated aliphatic and aromatic aldehydes was successfully conve
rted to acyloins. 19 of the biotransformation products identified had not b
een reported as natural substances before. Product yields were strongly aff
ected by substrate structure.